A variety of trim panels are used to form exterior surfaces on vehicles. Such trim panels have been formed of sheet metal, but are increasingly being formed using molded polymeric materials. One such trim panel is a rocker panel, sometimes referred to as a side sill, and is often used to form a show surface underneath side doors of vehicles. Various techniques have been used for attaching such rocker panels to the bodies of the vehicles. For example, rivets or threaded fasteners may be used for attaching the rocker panels to vehicle bodies.
Some rocker panels may be particularly close to the road. Given the proximity of the rocker panels to the road, it is not uncommon for portions of the rocker panels to come into contact with the road surface or curb. Thus, it may be desirable to provide rocker panels with structural features providing increased strength and resistance to damage.